1. Field of the Invention
The invention relates generally to devices and methods used in the protection and stabilization of shorelines, levees, earthen berms, and earthen terraces with a variety of soils and slopes, and more particularly to those devices and methods which create a living shoreline by trapping sediments that promote plant growth and establish a riparian edge for aquatic and wildlife habitat.
2. Description of Related Art
Erosion of coastal areas and shorelines, either through natural effects or caused by human activities, is a serious problem for many areas around the world. Many attempts have been made over the years to prevent or control such erosion, resulting in the development of various devices and methods which attentuate wave action and reinforce the shoreline using bulkheads, concrete structures, mats, and similar means.
Spangler (U.S. Pat. Publication No. 2002/0131826) discloses a modular fiber invention for erosion and sediment control. The fibers are slow decaying natural or synthetic fibers which contemplate that this product will degrade over time. The organic soils and erosion problems of coastal Louisiana require solutions that are more permanent in order to hold vegetation in place long enough to achieve growth and stabilization. In addition, Spangler would not be durable enough to handle the high wave energies in many coastal environments. The busting of sacks creates a problem as loose fibers are then scattered throughout the environment.
Molnar (U.S. Pat. No. 5,346,514) discloses sod mats with nylon sod reinforcements for use with sports fields and soil stabilization, also retarding weeds from growing into and through the mats from below. This patent does not address the problems of wave erosion in high energy environments and continuous boat wakes on large navigation channels. In this coastal environment all vegetative growth is necessary. Retarding vegetative growth from below would be counterproductive.
Finally, Kelly (U.S. Pat. No. 7,775,743) discloses a ground surface cover to reduce erosion of levees and shorelines anchoring a concrete matrix mat parallel to the shoreline. While this system does provide substantial protection from high energy waves, it does not include vegetation and thus does not create a living shoreline. The system described in Kelly is also very expensive and time consuming to install in comparison to the present invention.
Natural occurrences such as waves, hurricanes, and floods may destroy ecosystems, as well as wave action attributable to boat traffic and other vehicles. Over time, those ecosystems often recover and mature into diverse healthy environments. Without outside interference, the processes of recovery are normal and inevitable. They include microbial colonization followed by the invasion of plant species and eventually aquatic and wildlife species. In many areas, time is usually the only requirement for such recovery. However, the conditions, both naturally occurring and man-made, that are impacting the Louisiana coastline and similar regions do not allow for this spontaneous recovery. Shoreline erosion is dramatically affecting wetland loss. It is particularly rapid in large bays due to high wave energy and along navigation canals due to boat wakes and water surges associated with the passage of large vessels. The soils are highly organic peat and fluid, making it difficult to stabilize and protect. It is also difficult for newly planted vegetation along levees, berms and terraces to establish and grow because of the highly organic soils, which further contributes to the extensive wetland loss. To meet the challenges posed by the constant high-energy environment and human impact, intentional effort must be directed toward environmental restoration.
While such efforts have been successful to some degree, a primary goal in many areas is reformation and restoration of the shoreline to include native vegetation. In those instances, the objective is to stabilize and reinforce the areas subject to erosion with plants which are typically native to the region. Consequently, an organic ecosystem can eventually be established that is resistant to erosive forces, but using means which do not detract from the natural beauty of the shoreline. These methods are sometimes referred to as “living shorelines”, and they provide additional ecological habitat for aqueous as well as terrestrial biology. Living shorelines refers to management practices that use strategic placement of plants, stone, sand fill and other structural organic materials, such as oyster reefs, to provide shoreline stabilization and protection of marsh vegetation and habitat viability. Living shorelines may be used in appropriate areas as alternatives to bulkheads, rip-rap and other hard structures.
Because shoreline topography and conditions are so diverse, living shorelines must often be custom-designed for each location to be successful. According to most researchers, site-specific living shorelines must employ principles from each of the fields of ecology, geology, oceanography and engineering to develop effective projects.
To meet these needs, the present invention provides one of the most environmentally efficient and systematic efforts to harness the natural processes of the South Louisiana coastal ecosystem. The invention, in its preferred and alternative embodiments creates a living shoreline by stabilizing and protecting the existing earthen slope, while also promoting plant growth and establishing a riparian edge for aquatic and wildlife habitat.